Question

I am using the following code:

<ListBox 
    x:Name="lbItems"            
    Grid.Row="1"
    Margin="2">
    <ListBox.Template>
        <ControlTemplate>
            <Border 
                Background="{StaticResource DarkerBrush}"                            
                Width="{Binding Path=ActualWidth, RelativeSource={RelativeSource AncestorType={x:Type ListBox}, Mode=FindAncestor}}"
                BorderBrush="{StaticResource MediumBrush}"
                BorderThickness="0"
                CornerRadius="4">
                <ItemsPresenter />                            
            </Border>
        </ControlTemplate>
    </ListBox.Template>
</ListBox>

it works, but I see an exception in the Output Window that I would like to remove.

System.Windows.Data Information: 10 :
Cannot retrieve value using the
binding and no valid fallback value
exists; using default instead.
BindingExpression:Path=ActualWidth;
DataItem=null; target element is
‘Border’ (Name=”); target property is
‘Width’ (type ‘Double’)

Probably I am doing something not perfectly right, so do you have any idea how can I improve my code?

Answer 1

Width="{Binding ElementName=lbItems, Path=ActualWidth}" ?